1. Field of the Invention
The present invention relates to earth grading equipment, and more particularly, to a fine grader for fine grading the surface of a subgrade on which fresh concrete is to be poured.
2. Description of the Prior Art
A wide variety of related devices are disclosed in the prior art. U.S. Pat. No. 4,030,873 (Morrison) discloses a multiple section, varibable length vibratory screed which is translatable along the length of parallel oriented side forms for screeding the upper surface of freshly poured concrete.
U.S. Pat. No. 1,768,663 (Carr) discloses a tractor-drawn earth mold making machine which is translatable along the length of parallel oriented tracks which are positioned adjacent to an area in which concrete is to be poured. This device includes a plurality of blade sections and bracket means coupling each blade section to a horizontally oriented frame to permit independent orientation of each blade section with respect to the surface being graded. The bracket means permit the device to form the desired contour for the subgrade.
U.S. Pat. No. 3,352,036 (Miller) discloses a related type of fine grading apparatus which includes a plurality of hydraulic rams and associated linkage to adjust the width of the device and to vary the blade height of the device as required. U.S. Pat. No. 3,901,619 ('Agata) discloses a tractor-drawn grader which includes structure to permit the blade width, height and angle to be readily adjusted.
U.S. Pat. No. 1,949,151 (Fanfarillo) discloses a tractor-drawn roadway subgrader which is linerally translated along parallel oriented side rails and which includes a curved blade. U.S. Pat. No. 1,846,138 (Moore) discloses a concrete screed having a two element blade for imparting a contour to the upper surface of the concrete. The two ends of the screed overlap and are translated along a pair of parallel oriented side rails.
Other related prior art is disclosed in the following U.S. Pat. Nos. 1,978,464 (Leydecker); 1,936,209 (Reiland); 1,876,283 (Ennis); 1,741,825 (Carr) and 1,940,659 (Baker).